The idea of family heirlooms spanning generations and forming cobwebs of history is exotic in an Indiana Jones context - except the frequent reality is that all those boxes up in the attic contain nothing more than Grandpa's fraternity flask and Aunt Dottie's knitting needles.

Occasionally, though, there really are some treasures.

In Willimantic's Warehouse Gallery on a recent afternoon, with brittle winter sunshine angling through the windows, several items laid out on tables made up hundreds of years' worth of heirlooms from the intertwined Woodin and Caldwell families - whose members, over the years, have lived in Massachusetts, Rhode Island and Connecticut, including Old Saybrook.

The gallery houses Eldridge Auctions, and the pieces are part of a collection that will be go up for bid on Saturday.

"This is one of the bigger events we'll have over the course of a year or two," said Ernie Eldridge, who owns the business with his wife, Anita. "There are just some very nice pieces in this collection - but it's more than that. Occasionally, you'll see a collection that tells a great family story and sets down a history."

The Woodins and Caldwells were connected in the late 1800s when Sylvia Woodin married Frederick Caldwell in Toledo, Ohio.

Wandering through the facility, among examples of Chippendale and Sheridan furniture, silverware, muskets and weaponry, archival letters, journals and a ship's log, one is drawn to a glass-topped case of framed ancestral photographs and, in particular, a carved powder horn that belonged to American colonist Timothy Woodin. He carried the horn at the Second Battle of Fort Carillon - now known as Fort Ticonderoga - during the French and Indian War.

Looking at the powder horn and holding a thumb and index finger a few inches apart to demonstrate proximity, Steve Femiak, owner of Thames Import Co. in Niantic, said, "This horn is just this far from being a national treasure. When you think of the importance of the French and Indian War - it changed the way wars were fought and had a profound influence on George Washington, for example - something like this takes on added significance beyond just family history."

Femiak originally was contacted by the seller of the Woodin/Caldwell material, who wishes to remain anonymous. After examining the material with a colleague, Joan Bucko, Femiak knew it was a special collection.

"I couldn't have handled an auction of this size," Femiak said, "so I recommended Ernie, who's been a friend for years."

As the Eldridges began to assemble and organize the Woodin/Caldwell components and tangential material - auctioneers frequently compile from more than one source to round out any given event - it became apparent there were a lot of threads to the Woodin/Caldwell items. Bucko stepped in and provided research and documentation and was astounded by the unique context.

For example, on another table is an arrangement of photos, a journal, letters and a sword - all of which belonged to or were written by Commodore Charles Henry Bromedge Caldwell during the Civil War. In 1862, Caldwell led Union troops in a mission to remove chains blocking the Mississippi - an action that allowed Northern forces to capture New Orleans.

Yet another similar set of items - newspaper clippings, photographs, military IDs, uniforms and certificates - recount the efforts of Lt. Frederic Wyllys Caldwell, a World War I Army pilot.

After Caldwell perished in a crash in 1921, his sister, Dorothy Caldwell, began to archive materials from her brother's life. Her efforts branched out into an entire history of the two families. She gathered personal memorabilia from generations, then verified them historically through a variety of sources.

"It became clear that there was an extraordinary history here," Bucko said. "Dorothy kept meticulous records, and what we have are records that demonstrate there were family representatives in every major American war until 1921. Moreover, all of these people were individually very interesting and had fascinating lives. Together, it's astounding."

Portrait of Sylvia Woodin (later Caldwell) and her little brother Corey Woodin is one item from the Woodin/ Caldwell family that is going to auction Saturday.Dana Jensen/The DayBuy Photo

Ernie Eldridge of E.S. Eldridge Auctions, left, and Steve Femiak of Thames Imports in East Lyme look at a display case holding the Fort Ticonderoga powder horn used during the French and Indian War by Timothy Woodin. Items from the Woodin Caldwell family will be going up for auction at Warehouse Galleries in Willimantic Saturday.Dana Jensen/The DayBuy Photo

If you go

What: Public auction featuring items from the Woodin/Caldwell family collection